The Red Sox added three pitchers to their major league roster Monday before the 8 p.m. ET deadline for big league clubs to set their 40-man rosters in advance of next month’s Rule 5 Draft.

Boston selected left-hander Jalen Beeks and right-hander Chandler Shepherd to the major league roster from Triple-A Pawtucket, as well as right-hander Ty Buttrey from Double-A Portland.

The Rule 5 Draft, which is scheduled for the final day of next month’s Major League Baseball winter meetings (Dec. 14), allows clubs with open space on the 40-man roster to select Rule 5-eligible players from other organizations. Rule 5 eligibility is dependent on the age at which a player signed and that player’s experience, and Beeks, Shepherd and Buttrey all would have been available if the Red Sox didn’t add them to their 40-man roster before Monday’s deadline. (Click here for Rule 5 Draft rules, per MLB.com.)

Beeks, a 12th-round pick in 2014, is ranked the No. 16 prospect in the Red Sox organization, per MLB.com. The 24-year-old was named the Red Sox Minor League Pitcher of the Year for 2017 after going 11-8 with a 3.29 ERA in 26 starts spanning 145 innings between Portland and Pawtucket. He was teammates with Red Sox outfielder Andrew Benintendi at the University of Arkansas in 2014.

Shepherd, a 13th-round pick in 2014, is the franchise’s No. 21-ranked prospect. The 25-year-old spent his entire 2017 campaign with Pawtucket, making 33 relief appearances and one start. He posted a 1-5 record with two saves and a 4.07 ERA over 59 2/3 innings.

Buttrey, a fourth-round pick in 2012, went 2-5 with a 4.81 ERA over 63 2/3 innings in 40 relief appearances between Portland and Pawtucket this past season. The 24-year-old also pitched for Peoria in the Arizona Fall League.